UNIVERSITI PUTRA MALAYSIApsasir.upm.edu.my/5225/1/FK_2007_33a.pdf · Analisis unsur terhingga dan kerja eksperimen telah dijalankan bagi mengkaji kesan analisis penyerapan tenaga

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UNIVERSITI PUTRA MALAYSIA

DEVELOPMENT OF FIBER-REINFORCED EPOXY COMPOSITE ENERGY ABSORBER FOR AUTOMOTIVE BUMPER SYSTEM

MAJID DAVOODI MAKINEJAD

T FK 2007 33


By


Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia, in Fulfillment of the Requirement for the Degree of Master of Science

May 2007

ii

DEDICATION

A Special Dedication to My Kind Wife Mojgan and My Son Parsa For their Love and Support

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Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of the requirement for the degree of Master of Science


By


May 2007 Chairman : Mohd Sapuan Salit, PhD, PEng Faculty : Engineering Bumper is an important safety component in a vehicle. Approximately 70% of

damage claim occurred from low speed impact. In a number of European countries,

pedestrians contribute 12-35% of the number of severely injured or killed victims of

road traffic accidents. The bumper absorber plays an important role in energy

absorption in automotive bumper system. There are two types of energy absorber in

modern car. The first one is for low impact and another one for crashworthiness

impact. In the case of low impact test energy absorption, it normally uses foam as an

absorber which in some material cases is harmful and need more equipment for

production also there are uncompleted recovery after compression. Fiber reinforced

polymer composite material offers essential characteristics such as weight reduction,

design and manufacturing flexibility and safety improvement. In this research the

above-mentioned parameters and the inherent characteristics of fiber reinforced

polymer composite material have been used in designing polymer composite parts as

an energy absorber in automotive bumper system.

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In developing the reinforced polymer composite absorber the work of Neopolen_P

(2006) and AISI (2004) were followed as guides with some modifications. A series

of reinforced composite absorber was installed between fascia and beam in place of a

series of expanded polypropylene (EPP) absorber as was used by Neopolen_P

(2006).

The finite element analysis and experimental work were carried out to investigate the

effect of energy absorption analysis of the elliptical shape of the composite material.

The simulation was performed using a commercially available finite element

software package (LUSAS). It is found the ratio 150mm over 75 mm is suitable and the

fiber orientation [0],[90] are the best among [0], [10], [20], [30], [40], [45], [50],

[60], [70], [80], and [90] orientations.

The experimental work had been carried out to examine the effects of composite

elliptical absorber on energy absorption behavior subjected to quasi-static

compressive load. The composite elliptical absorber was fabricated from E- glass and

carbon fiber with the orientation of [0, 90], [0, 45,-45, 0] and [45, 0, 90]s. The load

and accumulative energy versus displacement were tested under compressive quasi-

static loading using the universal hydraulic testing machine (Instron 8500) and the

results were finally compared with FEA results.

It can be concluded that the composite absorber is useful in case of leg-form impact

in car bumper and repeated compression recovery is better than expanded

polypropylene (EPP) material and the equipment for manufacturing and number of

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parts are lower than EPP absorber. It can be used in different cars with various

spaces by small changing in production equipment.

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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Master Sains

PEMBANGUNAN KOMOSIT EPOKSI GENTIAN FIBER SEBAGAI

PENYERAP TENAGA UNTAK SISTEM BAMPER AUTOMOTIF

Oleh


Mei 2007

Pengerusi . : Mohd Sapuan Salit, PhD,PEng. Fakulti : Kejuruteraan Bamper adalah satu komponen keselamatan yang penting dalam sebuah kenderaan.

Kira-kira 70% daripada tuntutan kerosakan berlaku semasa hentaman berkelajuan

rendah. Dalam banyak negara Eropuh pejalan kaki menyumlang 12-35% kepada

bilangan mangsa yang cedera parah atau lerbunuh dalam kemalangan jalan raya.

Penyerap bamper mempunyai tugas utama dalam penyerapan tenaga dalam sistem

bamper automotif. Terdapat dua jenis penyerap tenaga dalam kereta moden. Yang

pertama adalah bagi hentaman rendah dan yang lain adalah bagi hentaman

kebolehancuran. Dalam kes penyerapan tenaga ujian hentaman rendah, ia biasanya

menggunakan busa sebagai penyerap di mana dalam sesetengah kes bahan adalah

merbahaya dan memerlukan lebih banyak peralatan bagi pengeluaran dan juga

terdapat pemulihan tidak lengkap selepas mampatan. Bahan komposit polimer

bertetulang gentian menawarkan ciri-ciri yang penting seperti pengurangan berat,

kefleksibelan reka bentuk dan pembuatan dan penambahbaikan keselamatan. Dalam

penyelidikan ini parameter yang disebutkan di atas serta ciri-ciri yang sedia ada

dalam bahan komposit polimer bertetulang gentian telah digunakan dalam mereka

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bentuk komponen komposit polimer sebagai penyerap tenaga boleh balik dalam

sistem bamper automotif.

Dalam membangunkan penyerap komposit polimer bertetulang kerja Neopolen_P

(2006) dan AISI (2004) telah diikuti sebagai panduan dengan sedikit

pengubahsuaian. Satu siri penyerap komposit bertetulang telah dipasangkan di antara

fascia dan rasuk bagi menggantikan satu siri penyerap polipropilena terkembang

(EPP) sebagaimana yang telah digunakan oleh Neopolen_P (2006).

Analisis unsur terhingga dan kerja eksperimen telah dijalankan bagi mengkaji kesan

analisis penyerapan tenaga bahan komposit yang berbentuk elips. Penyelakuan telah

dijalankan menggunakan pekej perisian unsur terhingga komersial (LUSAS). Adalah

didapati bahawa nisbah 150mm terhadap 75 mm adalah sesuai dan penghalaan gentian

[0] adalah yang terbaik daripada penghalaan[0], [10], [20], [30], [40], [45], [50],

[60], [70], [80], dan [90].

Kerja eksperimen telah dijalankan bagi mengkaji kesan penyerap elips komposit ke

atas kelakuan penyerapan tenaga yang dikenakan beban mampatan kuasi-statik.

Penyerap elips komposit telah difabrikasi daripada gentian kaca-E dan karbon

dengan penghalaan [0] dan [0, 45,-45, 0] dan [45, 0, 90]s penghalaan yang terbaik

adalah [0]. Beban dan tenaga tertumpuk lawan sesaran dan juga sejarah dan

kegagalan telah diuji di bawah bebanan kuasi-statik mampatan menggunakan mesin

pengujian hidraulik universal (Instron 8500) dan keputusan tersebut akhirnya

dibandingkan dengan keputusan FEA.

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Kesimpulan yang boleh dibuat ialah penyerap komposit adalah berguna dalam kes

hentuman bentuk kaki dalam bamper kereta dan penyerapan tenaga spesifik serta

pemulihan mampatan berulang-ulang adalah lebih baik daripada bahan polipropilena

terkembang (EPP) dan peralatan bagi pembuatan dan bilangan bahagian adalah lebih

rendah daripada penyerap EPP. Ia boleh digunakan dalam pelbagai jenis kereta

dengan ruangan yang berbeza dengan mengubah peralatan pengeluaran.

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ACKNOWLEDGEMENTS

Firstly, the author would like to express his sincere gratitude and deep thanks to the

Chairman of the Supervisor Committee Associate Professor Dr. Mohd Sapuan Salit

for his kind assistance, support, advice, encouragement, and suggestions this work

during the preparation of the thesis.

Furthermore, the author would like to take this opportunity my deepest appreciation

and gratitude to Associate Professor Dr. Robiah Yunus Member of Supervisory

Committee for her advice, valuable suggestion, encouragement, and comments,

throughout this work and during the preparation of this thesis.

Kindly the author would like to thank all staff at Universiti Putra Malaysia for their

help and support.

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I certify that an Examination Committee has met on 31/May/2007 to conduct the final examination of Majid Davoodi Makinejad on his Master of Science thesis entitled “Development of Fiber Reinforced Epoxy Composite Energy Absorber for Automotive Bumper System” in accordance with Universiti Pertanian Malaysia (Higher Degree) Act 1980 and Universiti Pertanian Malaysia (Higher Degree) Regulations 1981. The Committee recommends that the candidate be awarded the relevant degree. Members of the Examination Committee are as follows: Abdul Aziz bin Jaffar, PhD Lecturer Faculty of Engineering Universiti Putra Malaysia (Chairman) Megat Mohamad Hamdan b. Megat Ahmad, PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Internal Examiner) Aidy b.Ali, PhD Lecturer Faculty of Engineering Universiti Putra Malaysia (Internal Examiner) Jaafar Sahari, PhD Professor Faculty of Engineering Universiti Kebangsaan Malaysia (External Examiner)

HASANAH MOHD. GHAZALI, PhD Professor/Deputy Dean School of Graduate Studies Universiti Putra Malaysia Date: 3 AUGUST 2007

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This thesis submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfilment of the requirement for the degree of Master of Science. The members of the Supervisory Committee are as follows: Mohd Sapuan Salit, PhD,PEng. Associate Professor Faculty of Engineering Universiti Putra Malaysia (Chairman) Robiah Yunus, PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Member)

AINI IDERIS, PhD Professor/Dean School of Graduate Studies Universiti Putra Malaysia Date: 9 AUGUST 2007

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DECLARATION

I hereby declare that the thesis is based on my original work except for quotations and citations, which have been duly acknowledged. I also declare that it has not been previously or concurrently submitted for any other degree at UPM or other institutions. MAJID DAVOODI MAKINEJAD

Date: 30 JAUARY 2007

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TABLE OF CONTENTS

Page DEDICATION ii ABSTRACT iii ABSTRAK vi ACKNOWLEDGEMENTS ix APPROVAL x DECLARATION xii LIST OF TABLES xv LIST OF FIGURES LIST OF ABBREVIATIONS

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CHAPTER

1 INTRODUCTION 1.1 Background 1.1 1.2 Problem statement 1.3 1.3 Research objectives 1.4 1.4 Significance of the study 1.4 1.5 Scope and limitations of study 1.5 1.6 Thesis layout 1.6

2 LITERATURE REVIEW 2.1 Introduction 2.1 2.2 Bumper 2.1 2.2.1 The significance of bumper in vehicle 2.1 2.2.2 Main parts of bumper system 2.3 2.2.3 Bumper system classification 2.9 2.2.4 Conceptual design 2.13 2.2.5 New trend in bumper design 2.16 2.2.6 Bumper acceptance criteria 2.18 2.3 Composite 2.21 2.3.1 Major composite classes 2.22 2.3.2 Main components of composite 2.22 2.3.3 Fabrication of composite 2.27 2.3.4 Mechanical behavior of composite material 2.29 2.4 Analysis of energy absorbers 2.32 2.4.1 Finite element modeling of energy absorbers 2.32 2.4.2 Energy absorption calculation 2.44 2.4.3 Failure of fiber reinforced composite 2.46 2.5 Energy absorbers 2.47 2.5.1 Irreversible energy absorber 2.48 2.5.2 Reversible energy absorber 2.54 2.6 Summary 2.58

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3 METHODOLOGY 3.1 Introduction 3.1 3.2 Conceptual design 3.2

3.3 Structural development 3.4 3.4 Finite element analysis 3.5

3.4.1 Phases one (Ellipticity ratio) 3.9 3.4.2 Phase two (Fiber orientation) 3.9 3.5 Experimental work 3.10 3.5.1 Specimen fabrication 3.11 3.5.2 Fabrication process 3.13 3.5.3 Specimen test 3.14 3.6 Summary 3.15

4 RESULTS AND DISCUSSION 4.1 Introduction 4.1 4.2 Result of conceptual design 4.1 4.2.1 Bumper system 4.1 4.2.2 Reinforced composite energy absorber 4.3 4.3 Finite element analysis results 4.6 4.3.1 Ellipticity ratio results 4.6 4.3.3 Fiber orientation results 4.16 4.4 Experimental results and discussion 4.19

4.4.1 E-glass fiber results 4.19 4.4.2 E-glass and carbon fiber results 4.22

4.5 Calculation 4.28 4.6 Comparison between composite and EPP absorber 4.30 4.6.1 Recovery ratio of composite absorber 4.31 4.7 Summary 4.33

5 CONCLUSIONS AND RECOMENDATIONS 5.1 Conclusions 5.1 5.2 Recommendations for further research 5.2 REFERENCES R.1 APPENDICES A.1 BIODATA OF THE AUTHOR B.1

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LIST OF TABLES

Table Page

2.1 Property comparison between E-glass and S-glass 2.23

2.2 Main elements in E-glass and S-glass 2.25

2.3 Number of recent OEM pedestrian bumper publications and patents 2.59

3.1 E-glass and Carbon fiber properties 3.6

3.2 Properties of resin epoxy and hardener 3.13

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LIST OF FIGURES

Figure Page

1.1 Overall flow chart of the research 1.6

2.1 The optimized cross section of bumper beam 2.7

2.2 The typical beam section 2.7

2.3 Metal face bar system 2.11

2.4 Plastic fascia and reinforcing system 2.12

2.5 Plastic fascia, reinforcing beam, and energy- absorber 2.12

2.6 Plastic fascia, reinforcing beam and foam- system 2.13

2.7 Polymeric foam as an absorber 2.17

2.8 Polymeric foam as a reversible energy absorber 2.17

2.9 Sub-systems of tests used in the second phase of the EC directive

2.20

2.10 Proposed pedestrian ‘leg-form’ impact criteria 2.21

2.11 The manual and automatic hand lay-up manufacturing method 2.28

2.12 The filament winding method 2.30

2.13 S-S curve with fibers oriented in the direction of strain, random and traversal

2.32

2.14 Element shape 2.38

2.15 Prescribed loading 2.40

2.16

2.17

2.18

Typical response of an energy absorbing device and associated parameters Typical failure modes of composites

Ellipse under lateral loading

2.45

2.46

2.54

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2.19

2.20

2.21 2.22

Mechanical absorber

Shock absorber for energy absorption

Polymeric foam as an absorber

Elastomeric energy absorbing

2.55

2.56

2.57

2.58

3.1 Cross section of Neopolen_p 3.2

3.2 Flowchart of conceptual design 3.3

3.3 Developed energy absorber 3.5

3.4 Structure developed for FEA analysis 3.7

3.5 Finite element analysis flow chart 3.8

3.6 Work breakdown of experimental work 3.10

3.7 The drawings of mould 3.11

3.8 The mould used in the study 3.12

3.9 Cutting length of the fiber 3.12

4.1 Plastic fascia, foam, reinforcement beam and crush absorbing system

4.2

4.2 Schematic plan of EPP absorber 4.3

4.3 EPP reversible energy absorber 4.4

4.4 Reinforced epoxy energy absorber 4.4

4.5 Schematic plan of new concept 4.5

4.6 Detail of fixation method 4.6

4.7 Strain energy versus displacement (ratio=0.5) 4.7





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4.14 Strain energy versus displacement in various ellipticity ratios 4.14

4.15 Graphic view of strain in the absorber 4.15

4.16 Graphic view of displacement of the absorber 4.16

4.17 Material, angles, and number of layer 4.17

4.18 Strain energy versus displacement in different degree’s 4.17

4.19 Maximum total strain energy versus displacement 4.18

4.20 Variation of xyG versus fiber orientation 4.19

4.21 Load versus displacement in 0 degree of composite absorber 4.20

4.22 Energy absorption versus displacement 4.21

4.23 Glass fiber reinforced epoxy composite 4.22

4.22 Material, angles, and number of layer 4.15

4.17 Strain energy versus displacement 4.15

4.18 Total strain energy versus fiber angle 4.16

4.19 Variation of xyG versus fiber orientation 4.17

4.20 Load versus displacement in 0 degree of composite absorber 4.19

4.21 Energy absorption versus displacement 4.20

4.22 Glass fiber reinforced epoxy composite 4.21

4.23 Load versus displacement of carbon and E-glass fiber 4.22

4.24 Load versus displacement of carbon and E-glass 4.23

4.25 Energy absorption versus displacement in carbon and E-glass 4.24

4.26 Load versus displacement of E-glass 4.25

4.27 Energy absorption versus displacement in E-glass 4.26

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4.28 Load versus displacement in carbon fiber 4.27

4.29 Energy absorption versus displacement of carbon fiber 4.27

4.30 Comparison between FEA result and experimental 4.29

4.31 4.32

Stress verses strain of EPP absorber with density 65 (gr/lit)

Accumulative absorber energy of EPP and composite absorber

4.30

4.32

4.33 Recovery characteristic of EPP and composite absorbers upon repeated impact

4.33

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LIST OF ABBREVIATIONS

CCC CMC CTE EPDM EPP EPS FEA FEM FRC GE

xyG

IMC MMC NHSTA OEM PBT PC PP PMC PU

cdσ

tdσ

Carbon-Carbon Composites Ceramic Matrix Composites Coefficient of Thermal Expansion Ethylene Propylene Diene Monomer Expanded Polypropylene Expandable Polystyrene Finite Element Analysis Finite Element Method Fiber Reinforced Composite General Electric Shear Modulus Inter-Metallic Composites Metal Matrix Composites National Highway Safety Transport Administration Original Equipment Manufacturer Polybutylene Terephtalate Polycarbonate Polypropylene Polymer Matrix Composites Polyurethane Compression Tension Tension Stress

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RIM RRIM SEA SMC TSF UNECE

Reaction Injection Molding Reinforced Reaction Injection Molding Specific Energy Absorption Sheet Metal Compound Thick Sheet Forming United Nations Economic Commission for Europe

CHAPTER 1

INTRODUCTION

1.1 Background

As of 2002 there were 590 million passenger cars worldwide (roughly one car for

every eleven people), of which 140 million in the USA (approximately one car for

every two people).As automobiles increased in number and became larger and faster,

between 1945 and 1995, 2 million people died and about 200 million were injured in

automobile accidents—many more than were wounded and injured in all the wars in

the nation's history combined (Answers.com, 2006).In year 2005 328,264 road

accident, 47.012 road casualties, and 6200 road death was reported in Malaysia

which 3,523 (7.49%) is pedestrian accident and 7372 (15.68%) car accident

(Nizam,2005) and the cost of the road accidents in 2003 was about 9,374,000,000

RM (ADB-ASEAN,2003).

According to the Association of British Insurers report (ABI) in year 2002 about

70% of 10 billion Pounds of total annual cost of vehicle insurance is related to

damage repair from low speed impact crashes, and about 80% of damage claims

have no associated injury claim. It is clear that low speed crash constitutes a large

portion of the total cost to society for repairing crash vehicle. Consequently,

reducing vehicle damage in low speed crashes could have a massive global benefit.

Alignment of structures could also have a key part in ensuring better compatibility of

vehicles in higher speed crashes. Better bumper design could have a positive benefit

1.2

since bumper units are often the first components to connect in frontal car to car

crashes (Avery and Weeks, 2006).

From 1965 to 1995, more than fifty safety standards were imposed on vehicle

manufacturers, regulating the construction of windshields, safety belts, head

restraints, brakes, tires, lighting, door strength, roof strength, and bumper strength

(Answers.com, 2006). The North American and Canadian bumper performance

standards have been issued and it is more severe than European ones. The former

stipulates impact speed of 5 mph (8km/h) whereas the European pendulum impacts

are performed at 2.5 mph (4 km/h). There are no damages allowed to other parts of

the vehicle. Also the key to developing a bumper system capable to fulfill the

upcoming performance requirements as well as the design criteria lies in a

differential stiffness profile over a restricted total deformation. At the beginning of

the compression, the stress should be kept low to comply with pedestrian leg criteria,

after that the stiffness increase with increasing stroke to cover the energy absorption

necessary for 2.5 mph impact (Murata and Shioya, 2004).

Each bumper system consists of three main components namely bumper beam, fascia

and energy absorber (Sapuan et al., 2005).The energy absorber is a key part in

bumper system which has to dissipate the impact energy in collision. New bumper

system consists of two types of energy absorbers, low stiffener absorber which is

called the reversible absorber in this research and located between fascia and

reinforcement beam and the irreversible energy absorber which is consist of the

beam and the crushable energy absorber that it located at the back of the beam and

attached to the main face bar. Therefore the suitable geometry, light weight

1.3

materials, and study of mechanical properties in the limited packaging space in

design of the bumper absorber have to be precisely considered.

There are numerous works in crashworthiness energy absorption in different

applications such as airplane, ship and car industry, but there is linked the low

impact collision work developed to low impact test and reversible energy absorbing

system. In case of lower impact and pedestrian criteria the most common method

proposed for cushioning the lower limb in an impact uses an energy absorber (plastic

foam, egg-crate, spring steel, steel foam composites, crush-cans and plastic beam

(Schuster, 2006). The common material is expanded polypropylene foam which

demonstrates some essential properties for bumper absorber but it suffers from some

percentage of incomplete recovery after absorption. Different foam stiffness in a

unique part for obtaining different energy absorption to comply with the pedestrian

criteria causes some manufacturing problems (Murata and Shioya, 2004).Certain of

materials such as polyurethane exhales some toxic gas during production that is

harmful for worker.

1.2 Problem statements

Production of foam energy absorber not only needs some special equipment and

tools but also the production line must be control pressure, temperature, and mixing

rate. As well as some kind of material such as polyurethane foam exhales toxic gas

during production which is very harmful for workers. PU foam product need to

release the air trap after production and EPP foam need to store for post shrinkage at

least 8 hours.

Documents

UNIVERSITI PUTRA MALAYSIApsasir.upm.edu.my/5225/1/FK_2007_33a.pdf · Analisis unsur terhingga dan kerja eksperimen telah dijalankan bagi mengkaji kesan analisis penyerapan tenaga